Troglobites are rare and specialized animals that only live in dark caves. In this clip from the BBC’s Planet Earth: Caves, episode 4, we observe Thailand’s cave angel fish, the Texas Blind Salamander, and the Belizean White Crab. From wikipedia:
Troglobites typically have evolutionary adaptations to cave life. Examples of such adaptations include slow metabolism, loss of sight, and loss of skin pigment. Conversely, as opposed to lost or reduced functions, many species have extreme sensory adaptations for sense of touch or other stimuli that do not depend on light. Such adaptations may take the form of long antennae or sensory hairs, and other types of sensors, particularly chemosensory and auditory organs. Troglobites commonly do not survive well outside caves and therefore cannot travel between separate cave systems. As a result many species are endemic to a single cave or system of caves.
Good to know: Troglobite vs troglodyte. Related reading: The olm, the blind cave salamander that lives to 100.
Next: New Zealand’s Waitomo Glowworm Caves in 4K. Plus, don’t miss this: How the BBC makes Planet Earth look like a Hollywood movie.